1. Field of the Invention
This invention relates to bis(di-, tri- or tetra-substituted-cyclopentadienyl)zirconium dihalides, to a high-activity catalyst for the synthesis of polyolefins comprising the same, and to a process for producing polyolefins using said catalyst.
2. Description of the Prior Art
Since a catalyst comprising a bis(di-substituted-cyclopentadienyl)zirconium dichloride and methylaluminoxane was found to have high activity for polymerizing olefins [Japanese Patent Kokai No. 19309 (1983), and Makromol. Chem. Rapid Commun, 4, 417 (1983)], various types of zirconium compounds have been investigated as a component of olefinpolymerization catalysts.
As examples of cyclopentadienyl zirconium compounds having sustituent groups on the cyclopentadienyl ring so far synthesized, may be mentioned bis(methylcyclopentadienyl)zirconium dichloride [J. Chem. Soc. Dalton Trans., 805 (1981)], bis((pentamethylcyclopentadienyl)zirconium dichloride [J. Amer. Chem. Soc., 100, 3078 (1978)] and (pentamethylcyclopentadientyl)-(cyclopentadienyl)zirconium dichloride [J. Amer. Chem. Soc., 106, 6355 (1984)]. However, no zirconium compound having, as ligand, two di-, tri- or tetra-substituted-cyclopentadienyl radicals has yet been synthesized.
Use of compounds represented by the general formula of (C.sub.5 R.sub.m ').sub.p R.sub.s "(C.sub.5 R.sub.m ')MeQ.sub.3-p or R.sub.s "(C.sub.5 R.sub.m ').sub.2 MeQ as catalysts is described in Japanese Patent Kokai No. 35006 through No. 35008 (1985) and No. 296008 (1986), but no description can be found at all on the synthesis and properties of these compounds.
Japanese Patent Kokai No. 236804 (1986) describes a process for producing polyethylene wax with unsaturated bonds at terminals, but no description is made on the details of said unsaturated bonds.
These conventional Kaminsky catalysts have the problems that the yield and molecular weight of resultant polyolefins are not sufficiently high, and that there is no controlling the structure of said unsaturated bonds at terminals.